Patent GB-1378795-A (GB)
Title: Self adjusting connecting rods
IPC: F16D65/54
Filed: 1972-03-07
Abstract: 1378795 Linkwork; automatic slack adjusters for excessive and insufficient play R GUNTHART 7 March 1972 [10 March 1971] 10495/72 Headings F2K and F2E A self-adjusting variable length connecting- rod 7 in a railcar brake for obviating excessive or insufficient play in the brake system comprises two split segmented nuts 14, 22 radially inwardly garter spring clamped on to a threaded rod 12 within a housing 18, a relatively axially movable sleeve rod 13 spring-loaded at 19 within the housing 18, to normally bias the nut 14 against an abutment 17 of the housing 18 when the connecting-rod 7 is inactive, serving when outwardly, i.e. rightwardly, pulled during brake actuation to move the assembly by virtue of the brake play. Operation: Excess brake play correction.-The sleeve 13 is pulled rightwardly via an hydraulically actuated piston 9 and pivoted link 11 for brake actuation and moves the complete assembly 7 until the housing 18 is stationed by a stop 32, the sleeve 13 continuing to move rightwards releasing at 16 the nut 14 and engaging at coned surfaces 24, 25 the nut 22 which is thus locked on the rod 12 so as to continue to pull the rod 12 rightwards which carries the nut 14 until it contacts a rib 21 on the now stationary housing 18 and then simply ratchets along the threaded rod 12 to adjust its position thereon as the rod 12 is further pulled rightwardly for full brake engagement. On initial brake release the combined reaction loading of the brake release springs (not shown) and stressed brake linkages move the rod 12 together with the nut 14 and engaged sleeve 13 and nut 22 leftwards until nut 14 engages the abutment 17 of the housing 18 which is maintained stationary against the stop 32 by spring 19, the nut 14 then ratcheting back along the rod 12 to a correctly adjusted position thereon corresponding to the point at which the brakes are correctly released such that the return force on the rod 12 decreases rapidly below the locking grip of the expansible adjusting nut 14 thus immobilizing, i.e. stationing, the rod 12, the sleeve 13 being returned to its initial position within the assembly by the spring 19 such that the nut 22 ratchets along the rod 12 to a correspondingly currently adjusted position when the sleeve 13 re-engages the nut 14 (Fig. 2) to complete the length correction.  Insufficient brake play correction.-As before, brake actuation is effected by pulling-sleeve 13 together with the complete assembly 7 rightwards but due to insufficient brake play the rod 12 is initially retained against this displacement whereby the sleeve 13 disengages the extremity of the nut 14 and compresses the spring 19 to axially load the nut 14 through the housing abutment 17 whereby the nut 14 ratchets along the rod 12 according to the rightward displacement of the sleeve 13, the housing 18 following the nut 14 along the rod 12 until it is stopped, i.e. stationed by the stop 32. The movement of the ratcheting nut 14 along the rod 12 is relayed by a sleeve 29 to the split nut 22 which is correspondingly ratcheted along the rod 12 until a movement limiting lock-piece 27 slidably arranged within a slot of the nut 22 and non- axially movable relative the rod 12 engages the sleeve 29 to prevent further ratcheting movement of the nuts 14, 22 whereby the sleeve 13 engages the nut 22 as before forming a rigid connection therebetween for brake actuation, the function of the lock-piece 27 serving to limit the possible elongation to complete the length correction. A modified arrangement embodying similar features is illustrated in Fig. 3 (not shown).